Emerald Ash Borer Invades Oak Lawn

Oak Lawn has been infected by a plague of ash borers that are killing the village’s ash trees at an aggressive rate.

More than 1,500 white and green ash trees on mostly public parkways under the village’s jurisdiction are infected with the pest. This doesn’t include ash trees on school, park and private property.

The public works department’s arborist Heather Green described the ash borer infestation being at “epidemic proportions.”

“It’s very prevalent and aggressive. It kills trees very quickly,” Green said. “The ash borer can be inside a tree for five years before you notice it.”

For help in identifying, removing infected trees and preventing the spread of the emerald ash borer, check out LOCAL FACTS.

The emerald ash borer is an exotic beetle that was first discovered in southeastern Detroit 10 years ago, according to the national Emerald Ash Borer Information website.  Adult beetles feed on foliage but cause little damage. It’s the larvae that kill ash trees feeding on the inner bark disrupting the tree’s ability to transport water and nutrients.

The insect resembles a lightning bug but without the yellow belly. Put an ash borer under the light and it becomes a translucent metallic green.

Public works has removed about 70 of the infected ash trees, and will continue to remove trees throughout the winter.

“Winter is the best time to do most any tree work,” Green said. “There is no disease out or spores moving around affecting other ash trees.”

SEE MAP for village's ash trees.

Most of the ash trees found in Oak Lawn are of green and white ash variety. Many of the infected green ash trees are clustered around multi-family residences. Green ash has been the tree of choice for developers because they are fast growing and inexpensive.

The village will remove infected ash trees from the public parkway at no cost to the property owner. If, however, the tree is located on private property, the owner must remove the tree at his or her own expense.

Green said homeowners can prolong the lives of infected trees by having a qualified tree contractor or arborist inject them with insecticide at one- and three-year intervals. Such injections range in price from $100 to $300, but enable homeowners to save up for tree removal, which can cost up to $2,000.

"Trees can be injected for up to ten years, but eventually they will need to come down," she said.

Should the infected ash tree threaten the public right of way, the village can enforce an ordinance requiring the private property owner to remove it.

Earlier this month, approved an emerald ash borer management plan making the village eligible for a federal grant to help combat the disease. The Illinois Department of Agriculture has also enacted a quarrantine to prevent the artificial spread of the beetle through the transfer of infested wood and nursery stock.

If you suspect an ash tree in the public parkway to be infected with the beetle, contact the Oak Lawn Public Works Forestry Division at 708-499-7098. An expert will come out and evaluate the tree and determine its state of decline, and prioritize action as appropriate.

For a list of business-licensed tree contractors to help remove infected ash trees from private property, contact Deanne Adasiak in the village's economic development office at 708-499-7837.